1. Field of the Art
The present invention relates to a method for setting a timer circuit, especially in a fuse, there being used a setting unit for transferring the setting signal to the timer circuit.
The invention also relates to a device in such a timer circuit.
2. Prior Art Statement
Usually, the communication between the setting unit and the timer circuit in a fuse will be implemented by means of electro-mechanical contact connections on the outer surface of the fuse. However, in connection with such galvanic connections the possibility for contact problems will be present and increase with the number of contact points. It is therefore desired to reduce the number of contact connections to a minimum.
Conventional electronic digital timer circuits or stop watches in a fuse are based on the principle that the timer circuit is set by means of a number of time related pulses which correspond to the set time (frequency setting) of the timer circuit. In order to achieve a sufficient accuracy the time references in the setting unit and the fuse must be synchronized, a fact which involves that one of the two units must be calibrated in relation to the other. This seems to be an unnecessary procedure, and it also complicates the communication between the programming unit in the timer circuit and the setting unit.